Now instead of running in 31 seconds with 8 schedulers, this serial index build took (not surprisingly) 2 minutes and 10 seconds to build.

How many segments fell beneath the 1,048,576 row count?

This time, just one segment, the last one to be populated. With 117 segments (segment_id 0 through segment_id 117) populated at 1,048,576 per segment, and 123,695,104 rows – our 118th segment has the remaining 1,011,712 rows.

Should the more tightly packed segments provide meaningful performance gains versus the parallel-built, partially filled version? I haven’t tested this yet, but I will at some point. Let me know if you get a chance to do so before I do. My wild guess would be that the benefit would be minor, at best – but as with most things I would like to see for myself.